Accuracy of visual correction in photorefractive keratectomy.

PURPOSE: To investigate the accuracy of preoperative optical assessment and other factors that influenced the final visual outcome after photorefractive keratectomy (PRK). METHODS: The records of 126 eyes from 54 male and 72 female eyes were studied retrospectively, ranging from 6 months to 3 years post-PRK. Refractive errors ranged from low to high myopia and astigmatism, and proper and careful preoperative selection of patients was made. A single standard ablation zone (AZ) of 6.00 mm and transition zone (TZ) of 7.00 mm was made in all cases. RESULTS: The study population showed a high degree of accuracy in visual outcome. In simple myopia, 92.3% of female eyes and 84.1% of male eyes had a visual acuity of more than 6/9 or better. In myopia with astigmatism, 83.05% of female and 65.9% of male eyes had a visual acuity of 6/9 (20/40) or better. However, despite the residual myopia, whether with or induced astigmatism, post PRK visual acuity seemed to be less influenced by it, than as in the pre-PRK status. CONCLUSION: This study showed an accuracy in visual outcome of > 90% for females and > 80% for males. The Nidek EC-500 was satisfactory for its purpose.